Expansible pulley.



No. 698,854. Patented Apr. 29, I902.

' J. C. PRATT.

EXPANSIBLE PULLEY.

4 sheets Sheet (No Model.)

v No. 698,854.'

Paitented Apr. 29, I902. J. c. PRATT. EXPANSIBLE PULLEY.

(Application filed Mar. 15, 1901-) 4 Sheets-Sheet 2.

(No Model.)

THE nonms wrrcns 6a. mom'ufug. wunmn'rou, u a

No.'698,854. Patented Apr. '29, I902.

J.-c. PRATT EXPANSIBLE PULLEY.

(Application filed Mat. 15, 1901.)

-(No Model.) I 4 Sheets-Sheet 3 -No. 698,8.54. Patented Apr. 29, I902.

J. C. PRATT..

EXPANSIBLE PULLEY.

(Application filed Mar. 15, 1901.)

4 Sheets$heet 4.

(No Model.)

rrnn STATES ATENT FFIC JOHN C. PRATT OF HARTFORD, CONNECTICUT, ASSIGNOR CF ONE-HALF TO ARTHUR L; FOSTER, or HARTFORD, CONNECTICUT.

EXPANSIBLiE PU LLEY srnorrronrron forming part of Letters Patent No. 698,854, dated April 29, 1902. I Application filed March 15, 1901. Serial Nol,368.' (No model.) I

To all whom; it may concern: a power-driven vehicle. On said frame part Be it known that I, JOHN C. PRATT, a citioppositely-located bearings 12 are secured, in zen of the United States of America, residing which the shaft of the driving-Wheel is sup-- at Hartford, inthe county of Hartford and ported, and also in said frame part are simi- 5 State of Connecticut, haveinvented new and larbearings c, in which the shaft of the driven useful Improvements in Expansible Pulleys, wheel is supported. The driving-pulley is of which the following isa specification. indicated by d and the driven pulley by c. This invention relates to power transmis- Said bearings 11 and c are, as shown, made sion from one shaft to another by a flexible adjustable toward one another for the pur- I0 connection or belt and is inthe nature of an pose of applying the proper tension to the improvement on my two prior United States driving connection, (indicated clearly by f.) Letters Patent, dated December27, 1898, No. In principle of operation the expansion of 616,630, and December 18, 1900,No. 663,928. the driven wheel and the contraction of the The particular object of this invention is driving-wheel take place in precisely the 15 to provide collapsible and expansible driving same manner as described in my said prior and driven pulleys united by a flexible belt patents; but the manner of mounting these connection to self-propelled vehicles and in ,wheels and their connections with the drivcertain incidental improvements in details ing and driven pulleys and the application of construction, whereby the mechanism is of. two resistance-springs to each pulley and 20 adapted to the purpose specified and'whereby the fact that it has been found desirable that as wide a range as possible of the expansion .thepulleys should have a greater degree of and contraction of the pulleys maybe obexpansionand contraction havenecessitated tained. certain changes inconstruction of the sup- Referring to the drawings forming part'of ports and in the connections between the pul- 25 this specification, Figure 1 isa side elevation leys and the component parts of their drivof the driving and driven pulleys and their .ing'and transmittingmechanisms, which will driving connections between them, their. now be described.- shafts being shown in section'taken on line In mounting either of the wheels upon its 1 1, Fig. 2. Fig. 2 is a plan view of the pul jshaft'the hub t' is located axially between the 3o leys and their supports mounted in a suitable plates m, and said hub and the plates are proframe, certain portions being shown in sec vided with keyways p in the hub t' and r-in tion. Fig. 3 is a sectional view' through one the hubs q onthe'outside of the plates. These of the shafts on line 3 3, Fig. 2. Fig. at is a keyways'are of the same depth; but the ways section through Fig. 3 on line 4 4. Fig. 5 is in the hub t" are of somewhat-greater width 35 a perspective View of one end of aspring carthan those in the plates on. There are two ried on one of the pulley-shafts. Fig. 6 is a Qkeyways oppositely located both in the hubs 't' perspective view of portions of one of the and the hubs q, and when the side plates are pulleys, the parts beingin separated relation. in proper position relative to the hub 71, as Fig. 7 is a perspective view of a pair of the stated, the keys having one flanged'end are 40 links between two of the peripheral segments slipped into the keyways r and p. Theyfit of a wheel. Fig. dis a plan in section of one closely in the ways 7"; but the ways 19 being of said peripheral segments. Fig. 9 is another considerably wider than the key the hub 2' may plan and section of the same. Fig. 10 is a rotate relative to the plates 'm to an extent cross-section of one of said segments on line permitted by the excess of width of the key- 5 45 10 10, Fig. 8. Fig. ll-is a plan view, partly ways 19 over that of the ways 1".

insection, ofa modification of the spring con- To assemble the parts of either wheel, the

struction. Fig. 12 is a sectional side elevahub t is first placed on the shaft and is pinned tion of the same. or otherwise secured thereon. The radial Referring to the drawings, the devices are arms j are now pivotally secured to the ribs 50 shown supported in a suitable frame a, which of the hub in their proper order, and the side may be assumed to be a part of the frameof plates m are then slipped onto the shaft on each side of the hub t', and the rolls n on the arms are fitted into theirproper radial grooves on the inner surface of the plates m and connected with the segments y, and the links 2' being also properly located in their radial grooves in said plates m. The side plates beiug firmly held in position against the ends of the hub, the keys 8 are now passed through the keyways p and r, the head of the key lying in a recess in the end of the hub q, as shown in Fig. 6. Any suitable means for holding the keys sin their proper position maybe employed, as a set-screw through the hub q, for example. The hubs on the outside of the plates in are identical in construction and are each provided with notches t, with which projections on the ends of the spiral springs u interlock, the said springs being slipped over the shaft. The outer ends of said springs are pro vided also with projections which may enter sockets o in the hub of a pulley to, assuming that the wheel just described is applied to the bearings b. Said pulley w is provided with a long hub within which one of the springs 21. is located and which hub extends toward and close up to the wheel. On the opposite side of the wheel the spring uis inclosed in a long sleeve :0, which also extends from the outer end of the spring toward and close up to the side of the wheel. Both the pulley w and the sleeve .2: are rigidly attached to the shaft by set-screws located beyond the opposite extremilies of the springs u. This description of the mounting of one wheel will answer for both, as they are both identical in construction.

From the above description it will be observed that the operation of this construction,

assuming the above description to have been that of the driving-pulley d on the bearings 12, will be as follows: A suitable belt running over the pulley 20 rotates it, and through the interlocking connection of the pulley with the outer end of the spiral spring a, whose inner end interlocks with the hub g on that one of the side plates m nearest said pulley, will rotate said side plate, and the two side plates of the wheel being by meansof the keys 8 in direct connection with the hub 1 which is pinned to the shaft, there is a positive'driving connection between the pulley w and the driving-pulley (Z. It must be borne in mind, however, that the springs u tend to keep the .keys 8 to the rear side of the keywaysp in the hub-i and that all the power transmitted from the driving to the driven pulley will be measured bythe resistance of the springs a. By the expression rear side of the keyways is meant the rear side thereof as compared with the direction of movement ofthe pulley. Now when a draft exceeding the resistance of the spring u on the shaft g is applied to the periphery of the driving-wheel, for instance, then a movement of the arms j of said wheel in a direction inverse to the rotation thereof takes place, and under similar conditions the arms of the driven wheel will swing in the detail in Fig. 7) and areprovided at their united ends with rolls 2, which fit radial grooves 3, located between the grooves 0, as shown in'Figs. 1 and 6 clearly. The said arms 7', however, are somewhat difierent in construction from those shown in my said prior patents. In this construction, as shown in Fig. 1, every other arm is made of two parallel pieces suitably united-to move as one, the other arms being formed of a single piece, as shown. The ends of these arms are pivoted to the hub 2', as stated, by means of a pin passing through the circular flanges 7c and through the ends of these arms. The double arms are fitted over the outside of the flanges and the single arms are fitted in between the flanges. Therefore when the arms are in the position shown in Fig. 1, on the driven pulley e, for instance, when it isin its most contracted position diametrically, the single arm will lie between the two sides of the double arm, all as shown, and by means of this nesting arrangement a much greater range of expansibility is attainable than by the construction shown in my prior patents.

Another improvement over the construction shown in said prior patents relates to the segments 1 which consist in making said segments of cast metal,prc fer'ably malleable iron, having projections 4; onthe inclined faces thereof for the purpose of retaininga leather shoe 5, with which it has been desirable to line said segment for the purpose of increasing the frictional contact between it and the driving connection when the latter consists of V -shaped metal links. As an additional means for retaining these leather shoes rivets 6 may be passed down through the bottom of the groove in the segments and through the bottom of the latter.

In the drawings, referring now to Fig. 2, (I has been spoken of as the drivingpulley and e as the driven pnlley,d being driven by means of a belt rnnningonto the pulley 70 from a source of power, such as the engine of a motor-vehicle, power being transmitted from theshaft h by a belt running from another pulley 7, similar to the pulley w, connected with the driven wheel c, said belt on the pulley 7 running to the driving-axle of the vehicle.

It is, of course, obvious that any connection of the driving-pulleyd with a motor and any connection between the driven pulley e and the propelling-shaft of a vehicle may be substituted for the means described without departing from the spirit of the invention, the

means of transmission of power to the driving and from the driven wheel. I

In Figs. 11 and 12 a modification of the spring construction is shown. The springs shown in these figures and indicated by 8 have the same function as the springs u, (shown in Fig. 2,) and their operation is identical with the latter. The purpose of this modified construction is to permit a 'narrowing up of the construction as a whole.

In the construction shown in Fig. 2 one end of the springs 8 is connected directly to the plate 'm and the other end to the shaft. In said Figs. 11 and 12 the shaft is, preferably, solid and is indicated by 9, and there is sooured thereon an arm 10 by a set-screw 11 or other means, whose outer end bears on one end of said springs 8. The latter are in the form of an open coil and may be of such length as will give the desired degree of compression. The end of the spring opposite to that which the end of the arm 10 bears against abuts against a transverse partition 12, located in or forming part of an annular trough-shaped casing 13, which is screwed or otherwise secured to the side plate m concentrically. This casing is provided with a slot 14 on its inner wall to permit the swing of the arm 10. The preferable way of making this slot is to cut away the inner edge of the casing for a distance equal to the degree of movement of the arm and after assembling the parts lit in a piece 15 into said cut-away part, which will close up the opening, leaving only the said slot for the arm 10. The said piece 15 may be screwed to the plate or otherwise secured thereto either after the arm has been applied to the device or before, as desired. I place one spring on each of the plates m and connect therewith from the shaft, as shown, by means of an arm 10. The construction is very compact, and this form of a spring gives a greater relative movement of the shaft and plates than can be obtained by the use of the spring shown in Fig. 2. If desired, the spring may be placed in the annular casing 13 before the latter is screwed to the plate m, and to provide for this the stops 16 are located in the casing at about that point where the arm 10 will lie when the spring is not undertension, and the spring may be slightly compressed and put into the casing, one end bearing against the partition 12 and the other against said stops and the casing then secured to the plate, it being understood that the end of the arm is of such dimension as will permit it to come to a bearing on the spring between said stops 16.

Having thus described my invention, what I claim, and desire to secure by Letters Patent of the United States, is- I 1. The combination of two shafts of a driving'and a driven pulley of the class described,

one on each of said shafts, and a driving connection between them; each of said pulleys comprising a hub fixed on the shaft, annular side plates one on each side of said hub, loose on the shaft, and interlocking means between the hub and the plates, whereby the latter may rotate independently of the hub and shaft; arms between the plates pivoted by their inner ends on the hub and their outer ends having a sliding engagement with the plates; peripheralv segments on the outer ends of said arms, also located between the plates; spiral springs engaging by one end each of said plates, and by the opposite ends secured to the shaft; means for adjustably separating said shafts and for rotating one of them, substantially as described.

2. In an expansible and contractible pulley, a shaft, a wheel-hub fixed thereon, annular plates constituting the sides of the wheel located on said shaft, one each side of said hub, and loose on the shaft, interlocking means between said hub and plates whereby the latter may rotate relative to the shaft and hub; arms between the plates pivoted to said hub and having a sliding engagement with the plates, V-shaped peripheral segments on said arms and a lining in said segments, such as leather, and means for securing said lining; a spiral spring on each side of said pulley and engaging one plate of the latter by one end and secured to the shaft by the opposite end, and means for rotating the shaft, substantially as described.

3. In an expansible and contractible pulley or wheel, a shaft, a wheel-hub fixed thereon, annular plates constituting the sides of the wheel located on said shaft on each side of, and close to said hub and loose on said shaft, arms between said plates pivoted to said hub by one end, said latter end being curved to conform substantially to the hub, radial grooves in the inner surfaces of said plates with which the opposite ends of said arms en gage, and peripheral segments on said arms, a spiral spring, one of whose ends is in engagement with one of saidplates, and whose opposite end is in engagement with a member secured to said shaft, whereby the movement of said plate rotating on the shaft will compress said spring, substantially as de= scribed.

JOHN C. PRATT. Witnesses:

WM. H. OHAPIN, K. I. CLEMoNs.

ICC 

